LMC555CM Equivalent & Substitute Parts

Part Overview

The LMC555CM is a 555-type timer/oscillator IC manufactured by Texas Instruments, designed for clock and timing applications. Operating at 3MHz with a supply voltage range of 1.5V to 15V, this single timer IC is packaged in 8-SOIC surface mount configuration. The main part is currently in Last Time Buy status, indicating discontinued production. Equivalent and substitute parts are necessary to maintain design continuity and ensure long-term component availability for new production runs and field replacements.

Key Parameters

Parameter	Value
Part Number	LMC555CM
Manufacturer	Texas Instruments
Type	555 Type, Timer/Oscillator (Single)
Frequency	3MHz
Voltage - Supply	1.5V ~ 15V
Current - Supply	150 µA
Operating Temperature	-40°C ~ 85°C
Package / Case	8-SOIC (0.154", 3.90mm Width)
Mounting Type	Surface Mount
RoHS Status	RoHS non-compliant
Product Status	Last Time Buy

Substitute Part Grouping Explanation

Substitution of the LMC555CM is determined by the following critical parameters: package type (8-SOIC), mounting method (surface mount), functional category (555-type timer/oscillator), and electrical compatibility within specified voltage and current ranges. Substitute parts must maintain the same physical footprint and pinout to ensure PCB compatibility without layout modifications.

The substitute parts are grouped into two categories:

Direct Substitutes (Identical Packaging): Parts with tube or tape & reel packaging in 8-SOIC format that maintain full electrical and mechanical compatibility.

Functional Equivalents (Same Category, Different Electrical Specifications): Parts that operate as 555-type timers in 8-SOIC packaging but with different frequency ratings, supply voltage ranges, or current consumption. These require design verification to confirm suitability for the specific application.

Parameter Comparison

Part Number	Manufacturer	Frequency	Voltage - Supply	Current - Supply	Operating Temperature	Package	Packaging Type	RoHS Status	Product Status
LMC555CM	Texas Instruments	3MHz	1.5V ~ 15V	150 µA	-40°C ~ 85°C	8-SOIC	Tube	RoHS non-compliant	Last Time Buy
LMC555CM/NOPB	Texas Instruments	3MHz	1.5V ~ 15V	150 µA	-40°C ~ 85°C	8-SOIC	Tube	ROHS3 Compliant	Last Time Buy
LMC555CMX/NOPB	Texas Instruments	3MHz	1.5V ~ 15V	150 µA	-40°C ~ 85°C	8-SOIC	Tape & Reel (TR)	ROHS3 Compliant	Active
ICM7555CBAZ	Renesas Electronics Corporation	1MHz	2V ~ 18V	60 µA	0°C ~ 70°C	8-SOIC	Tube	ROHS3 Compliant	Active
ICM7555CBAZ-T	Renesas Electronics Corporation	1MHz	2V ~ 18V	60 µA	0°C ~ 70°C	8-SOIC	Cut Tape (CT) & Digi-Reel®	ROHS3 Compliant	Active
ICM7555IBAZ	Renesas Electronics Corporation	1MHz	2V ~ 18V	60 µA	-25°C ~ 85°C	8-SOIC	Tube	ROHS3 Compliant	Active
ICM7555IBAZ-T	Renesas Electronics Corporation	1MHz	2V ~ 18V	60 µA	-25°C ~ 85°C	8-SOIC	Cut Tape (CT) & Digi-Reel®	ROHS3 Compliant	Active
ICM7555ESA+	Analog Devices Inc./Maxim Integrated	500kHz	2V ~ 16.5V	30 µA	-40°C ~ 85°C	8-SOIC	Tube	ROHS3 Compliant	Active
ICM7555ESA+T	Analog Devices Inc./Maxim Integrated	500kHz	2V ~ 16.5V	30 µA	-40°C ~ 85°C	8-SOIC	Cut Tape (CT) & Digi-Reel®	ROHS3 Compliant	Active
ICM7555ISA+	Analog Devices Inc./Maxim Integrated	500kHz	2V ~ 16.5V	30 µA	-20°C ~ 85°C	8-SOIC	Tube	ROHS3 Compliant	Active
ALD7555SAL	Advanced Linear Devices Inc.	2.5MHz	2V ~ 10V	50 µA	0°C ~ 70°C	8-SOIC	Tube	ROHS3 Compliant	Active

Engineering Selection Recommendations

For Direct Replacement (No Design Changes Required):

LMC555CMX/NOPB is the primary recommended substitute. This part is manufactured by Texas Instruments, maintains identical electrical specifications (3MHz, 1.5V ~ 15V supply), and is in Active product status. The only difference is packaging format (Tape & Reel instead of Tube) and ROHS3 compliance. This part requires no circuit modifications and provides the highest compatibility assurance.

LMC555CM/NOPB serves as an alternative direct substitute with identical electrical performance and Tube packaging, also in Last Time Buy status with higher inventory availability (15,128 units).

For Functional Equivalents (Design Verification Required):

ICM7555IBAZ-T and ICM7555IBAZ (Renesas) operate at 1MHz with extended temperature range (-25°C ~ 85°C), matching the original part's lower temperature limit. These parts are in Active status with ROHS3 compliance and high inventory levels. Substitution requires verification that 1MHz operation is acceptable for the application.

ICM7555ESA+ and ICM7555ESA+T (Analog Devices/Maxim) operate at 500kHz with the lowest supply current (30 µA) and matching temperature range (-40°C ~ 85°C). These are suitable for power-sensitive applications but require confirmation that reduced frequency is compatible with circuit timing requirements.

ALD7555SAL (Advanced Linear Devices) operates at 2.5MHz with restricted supply voltage (2V ~ 10V) and narrower temperature range (0°C ~ 70°C). This part is suitable only for applications operating within these constraints.

All substitute parts maintain 8-SOIC package compatibility and surface mount mounting type, ensuring PCB footprint compatibility without layout redesign.

Frequently Asked Questions (FAQ)

Q: Can I use ICM7555CBAZ-T as a direct replacement for LMC555CM?

A: ICM7555CBAZ-T is functionally equivalent but not a direct replacement. While both are 555-type timers in 8-SOIC packaging, the ICM7555CBAZ-T operates at 1MHz (versus 3MHz for LMC555CM) and has a narrower operating temperature range (0°C ~ 70°C versus -40°C ~ 85°C). Substitution requires design verification to confirm that reduced frequency and temperature range are acceptable for your application.

Q: What is the difference between LMC555CM/NOPB and LMC555CMX/NOPB?

A: Both parts are manufactured by Texas Instruments with identical electrical specifications (3MHz, 1.5V ~ 15V, 150 µA). The primary difference is packaging: LMC555CM/NOPB is supplied in Tube format, while LMC555CMX/NOPB is supplied in Tape & Reel format. LMC555CMX/NOPB is in Active product status with higher inventory (31,756 units), making it the preferred choice for new designs. Both are ROHS3 compliant.

Q: Why do some substitute parts have lower frequency ratings?

A: Frequency rating reflects the maximum operating speed of the timer circuit. Parts like ICM7555ESA+ (500kHz) and ICM7555CBAZ (1MHz) are functionally equivalent 555-type timers but designed for lower-frequency applications. These can substitute the LMC555CM only if your circuit operates at or below their rated frequency. Using a lower-frequency part in a higher-frequency application will result in circuit malfunction.

Q: Are all substitute parts ROHS3 compliant?

A: All substitute parts listed are ROHS3 compliant. The original LMC555CM is RoHS non-compliant. If RoHS compliance is required for your application, use LMC555CM/NOPB or LMC555CMX/NOPB (both ROHS3 compliant Texas Instruments parts) for the most direct substitution path.

Q: Can I mix different packaging types (Tube vs. Tape & Reel) in production?

A: Packaging type affects handling and assembly processes but not electrical or mechanical compatibility. Tube and Tape & Reel versions of the same part number are electrically identical. However, production line equipment must be configured for the specific packaging format. Mixing packaging types requires coordination with assembly operations.

Q: What is the impact of different supply current ratings on my circuit?

A: Supply current (150 µA for LMC555CM, 60 µA for ICM7555CBAZ, 30 µA for ICM7555ESA+) affects power consumption and heat generation. Lower current consumption reduces power supply requirements and thermal load. If your circuit is power-constrained, a lower-current substitute may provide benefits. However, verify that the substitute part's frequency and voltage range remain compatible with your application requirements.

Q: Which substitute part has the widest operating temperature range?

A: LMC555CM, LMC555CM/NOPB, LMC555CMX/NOPB, ICM7555ESA+, and ICM7555ESA+T all operate across -40°C ~ 85°C. ICM7555IBAZ and ICM7555IBAZ-T extend to -25°C ~ 85°C. For applications requiring the full -40°C lower limit, select from the first group. For applications with narrower temperature requirements (0°C ~ 70°C), ALD7555SAL and ICM7555CBAZ variants are suitable.

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